1. Field of the Invention
This invention relates to post-mix beverage dispenser valves and more particularly to controlling the mixture ratio by modulating the flow rate of the water and syrup during operation.
2. Background
One well-known system for controlling the ratio of water to syrup in a beverage dispenser valve is to provide adjustable mechanical flow controls in each of the water and syrup conduits. These flow controls are used in conjunction with a solenoid valve in each conduit that opens when the valve is energized to dispense a beverage and which then closes after the beverage has been dispensed. A problem with such a system is that the mechanical flow controls need to be periodically adjusted to provide the correct ratio.
A more recent system (as described in U.S. Pat. No. 4,487,333, for example), controls the ratio automatically without the need for mechanical flow controls that require adjustment. This system uses solenoid valves in the water and syrup conduits that are intermittently turned on and off, independently, at prescribed duty cycles, to provide the desired mixture ratio.